My door tag on my my 07 MCS says 38psi cold for all four tires. Is that the optimum pressure, or is there a better setting for ride quality and tread life? I'm currently running a set of new Conti Extreme Contact DWS 205/45/17 standard tires(non run flats). When I picked my car up from from having them installed I checked the pressures a few days later only to find all four tires set to the max cold pressure of 51 psi. I immediately dropped them down to 42 in the front and 40 in the rear. The car feels a lot better now. I'm relying on the experience you all have had with tire pressures on these cars. Thank you.

I typically do 38 PSI on tires rated at a maximum of 50 PSI. With full-size tires, you should actually pressurize them based on the percentage of weight that is on each one compared to its maximum rated load. However, in my experience, this rule does not exactly apply to tires that have a lower profile. You want to maintain enough pressure to keep the small sidewalls shaped fairly well.